The political boundaries of different tribes expanded or
contracted with their good or ill fortune in battle.
Immigration often followed defeat, so that a clan, or
its offshoot is found at one period on one part of the
map and again on another. As _surnames_ were not generally
used either in Ireland or anywhere else, till after the
tenth century, the great families are distinguishable at
first, only by their tribe or clan names. Thus at the
north we have the Hy-Nial race; in the south the Eugenian
race, so called from Nial and Eoghan, their mutual
ancestors.

We have already compared the shape of Erin to a shield,
in which the four Provinces represented the four quarters.
Some shields have also _bosses_ or centre-pieces, and
the federal province of MEATH was the _boss_ of the old
Irish shield. The ancient Meath included both the present
counties of that name, stretching south to the Liffey,
and north to Armagh. It was the mensal demesne, or "board
of the king's table:" it was exempt from all taxes, except
those of the Ard-Righ, and its relations to the other
Provinces may be vaguely compared to those of the District
of Columbia to the several States of the North American
Union. ULSTER might then be defined by a line drawn from
Sligo Harbour to the mouth of the Boyne, the line being
notched here and there by the royal demesne of Meath;
LEINSTER stretched south from Dublin triangle-wise to
Waterford Harbour, but its inland line, towards the west,
was never very well defined, and this led to constant